Off-grid solar calculator
For a farmhouse, tubewell room or site with no electricity connection. Enter what will run and for how long each day, and you get the panels, UTL batteries, inverter, roof area and a price range. No phone number needed.
How it sizes an off-grid system
- List everything the site will use and the hours each runs a day. That gives the day’s units.
- The battery covers the units used after sunset, about 60% of the day’s total, plus any cloudy-day reserve you choose. Lithium is used to about 80% of its capacity and tubular to 50%, after 10% inverter losses.
- Panels make the whole day’s units in December and January, when fog cuts output to about 75% of the yearly average. Sizing for summer is the most common off-grid mistake.
- The inverter carries everything running at once plus a pump or fridge starting. Each kW of panels needs about 100 sq ft of shade-free roof.
- The price is our standard off-grid system of that size. Off-grid systems get no PM Surya Ghar subsidy, because they are not connected to PSPCL.
Off-grid solar systems covers the UTL kits and upkeep, and solar water pumps covers irrigation. If the site has a PSPCL connection, the hybrid calculator gives backup with the subsidy.
Typical off-grid systems
From the calculator. Prices are for our standard off-grid system of each size; the battery bank shown can change them.
| Case | Inverter | Battery | System | Roof | Installed |
|---|---|---|---|---|---|
| Farmhouse: lights, fans, fridge, TV, Wi-Fi, 1 HP pump, lithium | 3 kVA | 2 × lithium | 3 kW | 300 sq ft | ₹1,40,000 to 1,54,000 |
| The same with one cloudy day of reserve | 3 kVA | 3 × lithium | 3 kW | 300 sq ft | ₹1,40,000 to 1,54,000 |
| The same with tubular batteries | 3 kVA | 4 × tubular | 3 kW | 300 sq ft | ₹1,40,000 to 1,54,000 |
| Small site: lights, two fans and a TV only | 1 kVA | 1 × lithium | 1 kW | 100 sq ft | ₹47,000 to 51,000 |
The first case in full, as the calculator shows it.
Worked example: an off-grid farmhouse
Suggested system
3 kW off-grid
Makes and stores about 6.0 units a day for the appliances you chose, with no grid connection.
Needs about 300 sq ft of shade-free roof, at 100 sq ft per kW.
What goes into it
| Inverter1,617 W running together, plus starting surge | 3 kVA |
|---|---|
| Battery bankUTL 48 V, 100 Ah lithium, 9.6 kWh at 48 V | 2 × lithium |
| Solar panelsat least 3 kW for a foggy winter day | 3 kW |
| Roof area | about 300 sq ft |
| Units from the battery each night | 3.6 units |
Price
Estimated price range. Prices are indicative and subject to change. Contact us for the latest pricing and a customised quotation.
| 3 kW off-grid system, installedOur standard off-grid system of this size. The battery bank above can change the price, and we confirm it when we quote. | ₹1,40,000 to 1,54,000 |
|---|---|
| PM Surya Ghar subsidyoff-grid systems are not connected to PSPCL, so they don’t qualify | ₹0 |
Units by appliance
| Appliance | Units a day |
|---|---|
| 3 × Ceiling fans, regular | 2.3 |
| 1 × Refrigerator | 1.9 |
| 1 × Water pump, 1 HP | 0.5 |
| 8 × LED bulbs (9 W) | 0.4 |
| 1 × TV | 0.3 |
| 1 × Wi-Fi router | 0.2 |
| 2 × LED tube lights (20 W) | 0.2 |
| 1 × Mixer grinder | 0.1 |
Turn this into a quote
Send us the estimate and your address. We check the roof, the wiring and which circuits to back up, and come back with a system and a price.
This is an estimate for a first conversation. The inverter is sized to what runs together plus a motor starting, the battery to be used to about 80% (lithium) or 50% (tubular) each cycle, and the panels to 3.4 units per kW a day, less for winter fog. We fix the design after a site survey, and we don’t promise a particular backup time, bill or saving.
Questions we are asked
How many solar panels do I need for an off-grid system?
Enough to make a whole day’s units in December and January, not in summer. A farmhouse with lights, fans, a fridge, a TV and a 1 HP pump uses about 6.0 units a day and needs about 3 kW of panels.
How many batteries does an off-grid system need?
Enough for the night, plus any cloudy days you want covered. The farmhouse above needs about 3.6 units from the battery each night (2 UTL 48 V, 100 Ah lithium batteries). With one cloudy day of reserve that rises to about 9.7 units.
Lithium or tubular for off-grid?
An off-grid battery is used every night, so cycle life matters most. Lithium costs more to buy but lasts about twice as many cycles and needs no water, and it often works out cheaper over the years. Tubular is the lower-cost start.
Can an off-grid system run a water pump?
Yes, if the inverter can handle the pump starting. A 1 HP pump draws about three times its running power for a few seconds, which is why the farmhouse example needs a 3 kVA inverter. For a tubewell used for irrigation, a dedicated solar pump is usually the better choice.
Does an off-grid system get the PM Surya Ghar subsidy?
No. The subsidy is for grid-connected, net-metered systems. If the site has a PSPCL connection, a hybrid system gets the subsidy and still gives battery backup.
How much roof does an off-grid system need?
About 100 sq ft of shade-free roof per kW of panels. A 3 kW off-grid system needs about 300 sq ft, on a roof or a ground-mounted frame.